Liu Wenxu, Chen Zhe, Rong Li, Duan Xingwu, Qin Yuhong, Chun Zhenjie, Liu Xuening, Wu Jia, Wang Zihao, Liu Taicong
Yunnan Key Laboratory of Soil Erosion Prevention and Green Development, Yunnan University, Kunming 650500, China.
Yuanjiang Dry-Hot Valley Water and Soil Conservation Observation and Research Station of Yunnan Province, Institute of International Rivers and Eco-Security, Yunnan University, Kunming 650500, China.
Microorganisms. 2024 Jul 28;12(8):1546. doi: 10.3390/microorganisms12081546.
By changing the physicochemical and biological properties of soil, erosion profoundly affects soil nitrogen levels, but knowledge about the erosion impact on soil nitrogen (N) dynamics is still rather incomplete. We compared soil N contents at the early stage of vegetation self-restoration in response to soil erosion thickness (0, 10, 20, 30 and 40 cm), by conducting a simulated erosion experiment on sloping arable land in the dry-hot valley of Yunnan Province, southwestern China. The results showed total nitrogen (TN), ammonium nitrogen (NH-N) and nitrate nitrogen (NO-N) contents reduced with increasing soil erosion thickness and decreased significantly at the soil erosion thickness of 10, 40 and 10 cm in the rainy season and 30, 10 and 10 cm in the dry season compared with 0 cm. Structural equation modeling (SEM) indicated that soil erosion thickness and seasonal variation were the important drivers of mineral nitrogen (NH-N and NO-N) content. Soil erosion thickness indirectly affected mineral nitrogen through negative on TN, carbon content and Diazotrophs ( genes). Dry-wet season change had an effect on mineral nitrogen mediated by arbuscular mycorrhizal fungi (AMF) and genes. We also found AMF had a promotion to genes in eroded soil, which can be expected to benefit nitrogen fixing. Our findings highlight the importance of considering soil erosion thickness and sampling time for nitrogen dynamics, in particular, the investigation of nitrogen limitation, in the early stage of vegetation self-restoration.
通过改变土壤的物理化学和生物学特性，侵蚀对土壤氮水平产生深远影响，但关于侵蚀对土壤氮（N）动态影响的认识仍相当不完整。我们在中国西南部云南省干热河谷的坡耕地进行了模拟侵蚀实验，比较了植被自我恢复早期土壤氮含量对土壤侵蚀厚度（0、10、20、30和40厘米）的响应。结果表明，总氮（TN）、铵态氮（NH₄⁺-N）和硝态氮（NO₃⁻-N）含量随土壤侵蚀厚度增加而降低，与0厘米相比，雨季土壤侵蚀厚度为10、40和10厘米时以及旱季土壤侵蚀厚度为30、10和10厘米时显著降低。结构方程模型（SEM）表明，土壤侵蚀厚度和季节变化是矿质氮（NH₄⁺-N和NO₃⁻-N）含量的重要驱动因素。土壤侵蚀厚度通过对TN、碳含量和固氮菌（nifH基因）产生负面影响间接影响矿质氮。干湿季变化通过丛枝菌根真菌（AMF）和nifH基因对矿质氮产生影响。我们还发现AMF对侵蚀土壤中的nifH基因有促进作用，这有望有利于固氮。我们的研究结果突出了在植被自我恢复早期考虑土壤侵蚀厚度和采样时间对氮动态的重要性，特别是对氮限制的研究。
